Gastritis & H. Pylori Drugs

Question 1

Name all classes [6]

Answer 1

Antacids
H2 Antagonist
PPIs
Gastric Mucosal Protection [3]
- Sucralfate
- Misoprostol
- Bismuth

Question 2

Antacids

AE
Contra-I

Answer 2

Wek bases
Sodium/Calcium/Al hydroxides/bicarbs/carbonates

AE:

Milk-Alkali - hypercalcemia, drop PTH, Ca2+ excretion increases, Diuresis, GFR drops - Metabolic Alkalosis

CO2 - gastric distension, burping

Mg for diarrhoea; Al for constipation effects - give tgt ok

ContraI - check renal; dont eat w food

Question 3

H2 Blocker

Name, Instructions
AE

Answer 3

H2 receptor on Parietal cell receiving from ECL cells;

Famotidine, Cimetidine - FAMISHED, SEAMEN

• Take at night to block Nocturnal Secretion
• not good for meal-induced as other acid secreting factors like Gastrin and Ach

AE:
Cimetidine - anti-androgenic (testosterones/DHT), increases prolactin, leading to gynecomastia and galactorrhea (milky discharge)
- inhibit CYP
- mental confusion

Question 4

PPI

Name, Instructions
AE

Answer 4

Prazoles - Omeprazole

• Irreversible;
• Taken orally, travel by blood, activated by Acidic env
• Slight anti microbial

Dosage: 1 hr before breakfast

• 24 hr action
• need active pumps to block - H+-K+ ATPase
• bioavailability low w food

AE: Calcium deficiency, need Acid to absorb - hypochlorhydria Osteoporosis

Question 5

Sucralfate

Answer 5

Protective agent - sucrose salts complexed w Al

• sucrose sulfate w negative charge binds to positive proteins at the crater of ulcers - form Gel
• Al salt

AE: binds drugs, constipation (from aluminium)

Question 6

Bismuth

MOA [4]

Answer 6

Protective layer over ulcers from acid, pepsin
Stimulate Mucous, Bicarb secretion
Anti-microbial
Salicylate decreases inflammatory PG

AE: toxicity, encephalopathy, black stools, tongue

Question 7

Misoprostol

Answer 7

Synthetic PGE1
- prevent NSAID ulcers

Low conc: increases HCO3, mucous secretion, blood flow
High conc: block H+ secretion

AE: abortion from uterine contraction
hyperostosis, bone growth

Question 8

H. Pylori

Drugs + Timeline
1 AE

Answer 8

Clarithromycin + Amoxicillin/Metronidazole
PPI of Omeprazole (some direct antimicrobial)

Increase pH also lowers MIC for AB
7-14 days all 3 to kill H.Pylori, 4-6 weeks w PPI to heal ulcers

Second line add bismuth, also abit antimicrobial

AE: diarrhea